Honing tool for honing blind bores

ABSTRACT

The invention relates to a honing tool ( 1 ) that is suitable in particular for honing blind bores ( 5 ), comprising a stone carrier ( 3 ), a first honing stone segment ( 16 ) and a second honing stone segment ( 17 ). The first honing stone segment ( 16 ) and the second honing stone segment ( 17 ) are fastened in a groove ( 22 ) of the stone carrier ( 3 ). In addition, the stone carrier ( 3 ) comprises an end ( 10 ) with which the stone carrier ( 3 ) can be introduced into a bore ( 5 ). The second honing stone segment ( 17 ) is fastened closer to the end ( 10 ) of the stone carrier ( 3 ) than the first honing stone segment ( 16 ). Moreover, the wear resistance of the second honing stone segment ( 17 ) is greater than a wear resistance of the first honing stone segment ( 16 ). In this way, a straight bore ( 5 ) can be honed even in the case of limited idle travel ( 9 ).

BACKGROUND OF THE INVENTION

The invention relates to a honing tool that is suitable in particular for honing blind bores.

In order to hone a through bore, an idle travel is required at the upper and lower end of the bore. The required idle travel generally corresponds approximately to a third or the half of the honing stone length. In the case of a particular application, the actual idle travel is also determined by the shape of the bore. If, for example, the bore is narrower at the upper end than at the lower end, a larger idle travel is then required towards the top. If on the other hand the bore is narrower at the lower end, a larger idle travel is then necessary towards the bottom. By the correct selection of the idle travel, the bore is always kept straight. In the case of a blind bore, the lower idle travel is however severely limited. If the bore is now narrower at the bottom than at the top, the idle travel then cannot be increased towards the bottom for geometric reasons. As a result, the honing tool has to be removed relatively often. The honing stone can then be reworked on the honing tool, for example by regrinding, or a new honing stone must be used.

SUMMARY OF THE INVENTION

The honing tool according to the invention with the features of claim 1 has the advantage that a machining by honing is improved and is facilitated even in the case of unfavorable geometries. The invention also especially makes it possible for a straight bore to be honed in the case of small idle travel. This relates especially to an idle travel at the bottom of the bore.

It is advantageous that an additional honing stone segment is provided, that the additional honing stone segment can be fastened closer to the end of the stone carrier than the first honing stone segment, that the second honing stone segment can be fastened closer to the end of the stone carrier than the additional honing stone segment and that the additional honing stone segment has a wear resistance, which is greater than the wear resistance of the first honing stone segment and less than the wear resistance of the second honing stone segment. As a result, the honing stone segments, which are disposed closer to the end, do not wear down as fast as the honing stone segments which are disposed further away from the end of the stone carrier. The bore in the region of the end would thereby in fact become somewhat wider. This can however be compensated by increasing the idle travel on the other side of the bore.

It is advantageous that the honing stone segments together with the stone carrier have been assembled to form a honing stone and that the honing stone can be loosely disposed in a honing tool body. In so doing, it is further advantageous that the honing stone segments can be attached to the stone carrier by means of adhesive bonding or soldering and that said honing stone segments can again be removed by undoing the attachment. The honing stone segments in this case are preferably combined to form the honing stone so that the complete honing stone is connected to the stone carrier by means of adhesive bonding or soldering. If the honing stone is to be replaced by a new honing stone, the connection of said honing stone to the stone carrier is detached. As the case may be, a reworking of said honing stone, for example by finishing the surface thereof by grinding, can take place prior to replacing said honing stone.

In an advantageous manner, a groove is configured on the stone carrier, in which the honing stone segments can be inserted in a successive arrangement. Especially when combining the individual honing stone segments into a common honing stone, the successive arrangement is predefined by the assembly. By successively arranging the honing stone segments, a uniform machining of the bore is made possible.

It is also advantageous that the second honing stone segment, which has the greatest wear resistance, at least substantially adjoins the end of the stone carrier. In so doing, the honing stone or respectively the section which is composed of the honing stone segments wears less markedly in the region of the end of the stone carrier, and therefore an advantageous machining, which keeps the bore straight, is even achieved here in the case of limited idle travel.

It is also advantageous that between the second honing stone segment and the end of the stone carrier, an offset is formed which is on the end side and on which the second honing stone segment bears. Particularly in combination with the groove, in which the honing stone segments are inserted, a particularly good support of the honing stone segments on the stone carrier results as a consequence.

It is furthermore advantageous that the honing stone segments are disposed on one side of the honing stone body, that a supporting bar is provided and that the supporting bar is disposed on a further side of the honing stone body which faces away from said former side of the honing stone body. It is furthermore advantageous that the first honing stone segment is designed longer with respect to a longitudinal axis of the honing stone body than the second longitudinal axis segment. The machining of the bore by means of honing can therefore be performed to a great extent by the first honing stone segment, whereas the second honing stone segment and where applicable additional honing stone segments serve to compensate for the shortened idle travel at the end of the honing stone carrier by an intensified machining of the bore in this end region.

In an advantageous manner, the different wear resistances of the honing stone segments result from different specifications for a grit size and/or grit type and/or bond and/or concentration of the grits for the honing stone segments. This results in the honing stone segments not wearing down so fast in the region of the end by virtue of the fact that the honing stone carrier is equipped with honing stone segments of different specifications for the respective honing stone abrasive layer on the honing stone segments.

Longer tool lives of the honing tools, improved bore geometries and shorter machine downtimes can thus be achieved and therefore a greater operating efficiency is also achieved. In addition, advantages result with respect to mating parts having very tight tolerances, for example with respect to a pump piston and a pump cylinder, which have to be honed in a coordinated manner.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred exemplary embodiments of the invention are explained in detail in the following description with the aid of the attached drawings, in which corresponding elements are provided with matching reference numerals. In the drawings:

FIG. 1 shows a honing tool with a work piece in a schematic depiction according to a first exemplary embodiment of the invention;

FIG. 2 shows in extracts a depiction of the honing tool depicted in FIG. 1 of the first exemplary embodiment;

FIG. 3 shows in extracts a cross-sectional view through the honing tool depicted in FIG. 2 along a cut line denoted by III;

FIG. 4 shows the honing tool depicted in extracts in FIG. 2 according to a second exemplary embodiment;

FIG. 5 shows a honing tool in a schematic cross-sectional view depicted in extracts according to a possible configuration of the invention, in particular to illustrate the operation of an expansion bar, and

FIG. 6 shows a schematic cross-sectional view through the honing tool depicted in FIG. 5 along the cut line denoted by VI.

DETAILED DESCRIPTION

FIG. 1 shows a honing tool 1 and a work piece 2 in a schematic depiction according to a first exemplary embodiment of the invention.

The honing tool 1 comprises a stone carrier 3 (FIG. 2), a honing tool body 3′ and a cylindrical section 4, on which the honing tool 1 can be clamped into a chuck of a machine. By way of illustration, the honing tool 1 is introduced into a bore 5, which is configured as a blind bore 5. In this case, the blind bore 5 has an expanded section 7 at a lower end 6. In addition, provision is made for a bore 8 with reduced diameter, which opens out into the expanded section 7.

The expanded section 7 specifies a limited idle travel 9 for machining the bore using the honing tool 1. The limited idle travel 9 is hereby limited by a lower end of the honing tool body 3′ striking against the lower end 6 of the expanded section 7.

The honing tool 1 has a longitudinal axis 15. In order to machine the bore 5, the honing tool 1 is displaced in the direction of the longitudinal axis 15. The bore 5 is honed by means of this displacement. A first honing stone segment 16, a second honing stone segment 17 and in this exemplary embodiment furthermore an additional honing stone segment 18 are hereby provided to hone the bore 5. In this case, the additional honing stone segment 18 is disposed between the first honing stone segment 16 and the second honing stone segment. In this exemplary embodiment, the honing stone segments 16, 17, 18 are combined with the stone carrier 3 to form a honing stone 19. The honing stone segments 16, 17, 18 are thereby fastened to the stone carrier 3. The attachment can, for example, result from adhesive bonding or soldering. The honing stone segments 16, 17, 18 can then again be detached in order to replace said segments at the end of the service life thereof.

As viewed from the lower end 10 of the stone carrier 3 or respectively the honing tool body 3′, the second honing stone segment 17, the additional honing stone segment 18 and the first honing stone segment 16 are successively mounted on the stone carrier 3, wherein initially the second honing stone segment 17, then the additional honing stone segment 18 and finally the first honing stone segment 16 are mounted as the respective segment of the honing stone 19 on the stone carrier 3. The honing stone segments 16 to 18 have different wear resistances. In this case, the wear resistance decreases across the honing stone segments 16 to 18 when viewed from the lower end 10. The second honing stone segment 17 has the greatest wear resistance. The first honing stone segment 16 has the least wear resistance. The wear resistance of the additional honing stone segment 18 lies between the wear resistance of the first honing stone segment 16 and the wear resistance of the second honing stone segment 17.

In this exemplary embodiment, an idle travel of arbitrary size for machining the bore 5 with the honing tool 1 is present at the upper end of said bore 5. By an appropriate selection of the idle travel, an advantageous machining on part of the honing stone 19 can thus take place in said bore 5 up to the upper end 20 thereof, wherein the machining substantially results from the first honing stone segment 16.

The conditions are different on the lower end 6 of the bore 5. The part of the bore 5 to be machined ends in a region 21, and therefore only the limited idle travel 9 is available with respect to the region 21. This limitation is compensated for by the greater wear resistance of the honing stone segments 17, 18. If an idle travel of arbitrary size were available, which could be used in accordance with a normal honing operation, this would then result in an expansion of the bore 5 in the region 21 due to the increased wear resistance of said honing stone segments. If on the other hand the bore 5 were machined with a honing stone 19, which did not comprise different segments having different wear resistances, the limitation of the idle travel would result in a relative constriction of the bore 5 in the region 21 with respect to the remaining portion of said bore 5. A suitable selection of the wear resistances of the honing stone segments 16 to 18 achieves the result of having the two effects, namely the combination of increased wear resistance of the honing stone segments 17, 18 and the limitation of the idle travel 9, at least approximately offset each other. A uniformly configured bore can thus be produced by the honing tool 1.

The honing stone 19 is disposed on one side 30 of the honing tool body 3′. At least one supporting bar 32 is mounted in the region of a further side 31, which faces away from the side 30. The supporting bar 32 is thereby preferably exactly as long as the honing stone 19. In addition, said supporting bar 32 preferably extends over the same longitudinal section of the honing tool body 3′ as the honing stone 19. During honing, said supporting bar 32 ensures stabilization of the honing tool in the bore 5 so that a uniform honing is facilitated when machining said bore 5 with the honing stone 19. Hence, a geometric improvement to a honed blind bore 5 is possible through the use of the specifically segmented honing stone 19.

FIG. 2 shows in extracts the honing tool depicted in FIG. 1 in a schematic cross-sectional representation. The stone carrier 3 has a groove 22, in which the honing stone segments 16, 17, 18 are inserted. The second honing stone segment 17 is disposed in the groove 22 closest to the lower end 10 of the stone carrier 3. In this exemplary embodiment, the second honing stone segment 17 substantially adjoins the end 10 of the stone carrier 3. Between the second honing stone segment 17 and the end 10 of the stone carrier 3, an offset 23 is thereby formed, which is on the end side and on which the second honing stone segment 17 bears. In this exemplary embodiment, the offset 23 is formed by the recess 22 which produces the groove 22. As a result of the groove 22 being formed in the stone carrier 3, a further offset 24 is additionally formed, on which the first honing stone segment 16 upwardly bears. In this exemplary embodiment, the honing stone segments 16, 17, 18 bear therefore on the one hand on the offset 23 and on the other hand on the offset 24.

A better purchase of the honing stone segments 16, 17, 18 on the stone carrier 3 can be ensured by the groove 22, in which said honing stone segments 16, 17, 18 are inserted. In so doing, said honing stone segments 16, 17, 18 can be set into the groove 22. Said honing stone segments 16, 17, 18 are thereby preferably connected to the stone carrier 3 by means of adhesive bonding. A connection by means of soldering is also possible.

FIG. 3 shows in extracts the honing tool 1 depicted in FIG. 2 in a cross-sectional representation along the cut line. Lateral ribs 25, 26, which extend parallel to the longitudinal axis 15, are formed by the configuration of the groove in the stone carrier 3. The lateral ribs 25 improve the connection and the purchase of the honing stone segments 16, 17, 18 with the stone carrier 3. Forces acting laterally on the individual honing stone segments 16, 17, 18 can particularly be absorbed by the positive-locking connection.

FIG. 4 shows in extracts a honing tool 1 in a schematic cross-sectional representation according to a second exemplary embodiment. In this exemplary embodiment, the honing stone 19 is composed of the first honing stone segment 16 and the second honing stone segment 17 as well as the stone carrier 3. In this case, the first honing stone segment 16 is designed significantly longer than the second honing stone segment 17. In fact, the first honing stone segment 16 is designed longer than each of the honing stone segments 17, 18 in the first exemplary embodiment described with the aid of FIG. 2. The first honing stone segment 16 is also preferably longer than the sum of the lengths of the second honing stone segment 17 and one or a plurality of additional honing stone segments 18.

FIG. 5 shows in extracts a honing tool 1 in a schematic cross-sectional representation according to a possible embodiment of the invention. In this case, an expansion bar 40 is depicted, which is inserted into an axial bore 41 of the honing tool carrier 3′. The expansion bar 40 serves to retain the honing stone 19 in the honing tool carrier 3′ and if need be to discharge the former out of the latter.

The honing stone segments 16, 17, 18 are adhesively bonded or soldered to the stone carrier 3. The stone carrier 3 and said honing stone segments 16, 17, 18 then form the honing stone 19, which is inserted into a groove 42 of the honing tool body 3′. In so doing, the honing stone 19 remains loose in said honing tool body 3′, and therefore the honing stone can move inwardly or outwardly.

FIG. 6 shows a schematic cross section through the honing tool 1 depicted in FIG. 5 along the cut line denoted with VI. Two supporting bars 32, 32′, which are fixedly connected to the honing tool body 3′, are mounted in the region of the side 31 of said honing tool body 3′. The connection can, for example, result from adhesive bonding or soldering. The supporting bars 32, 32′ brace the honing tool 1.

The invention is not limited to the exemplary embodiments which have been described. 

1. A honing tool (1) comprising a stone carrier (3), a first honing stone segment (16) and at least a second honing stone segment (17), wherein the first honing stone segment (16) and the second honing stone segment (17) can be fastened to the stone carrier (3), wherein the stone carrier (3) comprises an end (10) with which said stone carrier (3) can be introduced into a bore (5), wherein the second honing stone segment (17) can be fastened closer to the end (10) of said stone carrier (3) than the first honing stone segment (16) and wherein said second honing stone segment (17) has a wear resistance which is greater than a wear resistance of said first honing stone segment (16).
 2. The honing tool according to claim 1, characterized in that at least one additional honing stone segment (18) is provided, in that the additional honing stone segment (18) can be fastened closer to the end (10) of the stone carrier (3) than the first honing stone segment (16), in that the second honing stone segment (17) can be fastened closer to the end (10) of the stone carrier (3) than the additional honing stone segment (18) and in that the additional honing stone segment (18) has a wear resistance which is greater than the wear resistance of the first honing stone segment (16) and less than the wear resistance of the second honing stone segment (17).
 3. The honing tool according to claim 1 or 2, characterized in that the honing stone segments (16, 17) together with the stone carrier (3) are assembled to form a honing stone (19) and in that the honing stone (19) can be loosely disposed in a honing tool body (3′).
 4. The honing tool according to claim 1, characterized in that the honing stone segments (16, 17) can be removably connected to the stone carrier (3) by adhesive bonding or soldering.
 5. The honing tool according to claim 1, characterized in that a groove (22) is configured on the stone carrier (3), in which groove the honing stone segments (16, 17) can be inserted in a successive arrangement.
 6. The honing tool according to claim 1, characterized in that the second honing stone segment (17) at least substantially adjoins the end (10) of the stone carrier (3).
 7. The honing tool according to claim 6, characterized in that between the second honing stone segment (17) and the end (10) of the stone carrier (3), an offset (23) is formed on an end side, the second honing stone segment (17) bearing on said offset.
 8. The honing tool according to claim 7, characterized in that the honing stone segments (16, 17) are disposed on a side (30), in that at least one supporting bar (32) is provided and in that the supporting bar (32) is disposed in the region of a further side (31) which faces away from the side (30).
 9. The honing tool according to claim 1, characterized in that the first honing stone segment (16) is longer with respect to a longitudinal axis (15) than the second honing stone segment (17).
 10. The honing tool according to claim 1, characterized in that the different wear resistances of the honing stone segments (16, 17) result from different specifications for at least one of a grit size, a grit type, a bond and a concentration of grits for the honing stone segments (16, 17).
 11. A honing tool (1) comprising a stone carrier (3), a first honing stone segment (16) and a second honing stone segment (17), wherein the first honing stone segment (16) and the second honing stone segment (17) are fastened to the stone carrier (3), wherein the stone carrier (3) comprises an end (10) with which said stone carrier (3) can be introduced into a bore (5), wherein the second honing stone segment (17) is fastened closer to the end (10) of said stone carrier (3) than the first honing stone segment (16) and wherein said second honing stone segment (17) has a wear resistance which is greater than a wear resistance of said first honing stone segment (16).
 12. The honing tool according to claim 11, characterized in that at least one additional honing stone segment (18) is provided, in that the additional honing stone segment (18) is fastened closer to the end (10) of the stone carrier (3) than the first honing stone segment (16), in that the second honing stone segment (17) is fastened closer to the end (10) of the stone carrier (3) than the additional honing stone segment (18) and in that the additional honing stone segment (18) has a wear resistance which is greater than the wear resistance of the first honing stone segment (16) and less than the wear resistance of the second honing stone segment (17).
 13. The honing tool according to claim 11, characterized in that the honing stone segments (16, 17) together with the stone carrier (3) are assembled to form a honing stone (19) and in that the honing stone (19) is loosely disposed in a honing tool body (3′).
 14. The honing tool according to claim 11, characterized in that the honing stone segments (16, 17) are removably connected to the stone carrier (3) by adhesive bonding or soldering.
 15. The honing tool according to claim 11, characterized in that a groove (22) is configured on the stone carrier (3), in which groove the honing stone segments (16, 17) are inserted in a successive arrangement.
 16. The honing tool according to claim 11, characterized in that the second honing stone segment (17) at least substantially adjoins the end (10) of the stone carrier (3).
 17. The honing tool according to claim 16, characterized in that between the second honing stone segment (17) and the end (10) of the stone carrier (3), an offset (23) is formed on an end side, the second honing stone segment (17) bearing on said offset.
 18. The honing tool according to claim 17, characterized in that the honing stone segments (16, 17) are disposed on a side (30), in that at least one supporting bar (32) is provided and in that the supporting bar (32) is disposed in the region of a further side (31) which faces away from the side (30).
 19. The honing tool according to claim 11, characterized in that the first honing stone segment (16) is longer with respect to a longitudinal axis (15) than the second honing stone segment (17).
 20. The honing tool according to claim 11, characterized in that the different wear resistances of the honing stone segments (16, 17) result from different specifications for at least one of a grit size, a grit type, a bond and a concentration of grits for the honing stone segments (16, 17). 